Allow me to rephrase, there is no "specified" break-in period in my '04 manual anyway.
To quote (sec 4-pg#7, 2004 Mazda3 owner's manual):

"Break-In Period
No special break-in period is necessary, but afew precautions in the first 1000km (600 miles) may add to the performance, economy and life of your Mazda:
[ul][*]Don't race the engine.[*]Don't maintain one constant speed, either slow or fast, for a long period of time.[*]Don't drive constantly at full-throttle or high engine rpm for extended periods of time.[*]Avoid unnecessary hard stops.[*]Avoid full-throttle starts."[/ul]
But in reality, what's the rush? The more time you give the engine to "break-in" properly (within reason of course)the better, imo.

 

I run Semi Synthetic in mine, I also change my oil about every 5 to 6weeks (depending on how many times I take the work truck home) with the mileage I put on it.

 

I wasextremely gentle on my car until I hit 1000 miles on the ODO. As in keeping revs below 3500 rpm, full time granny acceleration, and keeping my speed under 65 mph. It was difficult to keep the discipline! That was my way of applying what is in the manual (see Virgin1's post above).

Even now, Ipretty much never rev it past4000 rpm (to me, the 2.0 "feels" a little strained beyond 4000),I rarely gun it, 99% of the time my RPMs are between 2000 and 3000. I stillaccelerate like a granny until I see the temp needle move - I believe in letting the engine warm up before pushing it. I'm in it to make this baby last ... plus with gas costing what it does at the moment, I'm all about maximizing MPG.

 

I strongly agree with that statement. It's NEVER, EVER a good idea to push an engine before waterAND oil temperature are reached. It often takestwice as long to achieve oil temp as water temp. (<< an educated guess and it will vary w/ambient temp, load, etc.) I myself baby mine to this day until I've gone approx 5-7 miles, but drive it gently, don't let it idle to temperature. 0 mpg, and it takes forever. You're much better letting it warm up while in under-load conditions.

Uber, You may feel it's straining because of the shorter stroke/greater piston speed and velocity. The 327ci I used to have felt the same way in the upper rpm band. It was a weird feeling compared to other longer stroked engine I was familiar with, but it doesn't really hurt it. You just have less torque available up there.

 

speaking of RPM i did the advance timing mod and i only feel the power above 5 grand...i don't feel that umfph if you know what i mean.